Минералого-петрографические особенности и последовательность образования золотосурьмяных руд Удерейского месторождения (Красноярский край)

The article presents results of petrographic and mineralogical studies of gold-antimony ores of the Udereyskoe deposit and their concentration products. The main mineral associations of ores are characterized, mineral forms of occurrence are revealed, and distribution of Au, Pd, Ag is estimated. The paragenetic scheme of mineral formation sequence was clarified and supplemented. The important mineral forms of gold occurrence are goldbearing arsenopyrite and native gold (Au,Ag), as well as rare aurostibite AuSb2 and intermetallides such as antimony gold (Au,Sb), and palladium gold (Au,Pd). The revealed diversity of forms of noble metals and analysis of their relationships with associating sulfides and nonmetallic minerals indicate at least two contrasting early and late stages of ore genesis. Early quartz-pyrite and late pyrite, which are two stages of mineralization, are determened within the early stage. Three consecutive stages of mineralization are established in the late stage: quartz-stibnite, pyrite-stibnite-quartz, and pyrite-arsenopyrite-stibnite.Приводятся данные по петрографическим и минералогическим исследованиям исходных золотосурьмяных руд Удерейского месторождения и продуктов их обогащения. Охарактеризованы главные минеральные ассоциации руд, выявлены минеральные формы нахождения и оценено распределение Au, Pd, Ag. Уточнена и дополнена парагенетическая схема последовательности минералообразования. Важными минеральными формами нахождения золота являются преобладающие золотосодержащий арсенопирит и самородное золото (Au,Ag), а также редкие ауростибит AuSb2 и интерметаллиды – сурьмянистое золото (Au,Sb) и палладистое золото (Au,Pd). Выявленное многообразие форм нахождения благородных металлов и анализ их взаимоотношений с ассоциирующими сульфидами и нерудными минералами указывают на как минимум два контрастных этапа рудогенеза – ранний и поздний. В пределах раннего этапа выделены две стадии минерализации – ранняя кварц-пиритовая и поздняя колчеданная. В позднем этапе выделены три последовательные стадии минерализации: кварц-стибнитовая, пирит-стибнит-кварцевая и пирит-арсенопирит-стибнитовая

Thermally stable composite system Al2O3-Ce 0.75Zr0.25O2 for automotive three-way catalysts

Present-day three-way catalysts operate in contact with exhaust gases whose temperature is as high as >1000 C, so the problem of developing thermally stable catalytic compositions is still topical. A series of Al2O 3-Ce0.75Zr0.25O2 composites containing 0, 10, 25, and 50 wt % Al2O3 has been synthesized by direct precipitation. The as-prepared composites and those calcined in air at 1000 and 1100 C have been characterized by BET, X-ray diffraction, transmission electron microscopy, and temperature-programmed reduction methods. The composites aged at 1050 C in a 2% O2 + 10% H2O + 88% N2 atmosphere have been used to prepare monolith catalysts, and the oxygen storage capacity (OSC) of the latter has been measured using a gas analysis setup. As the proportion of Al2O 3 in the composite is raised, the mixing uniformity and degree of dispersion of Ce x Zr1-x O2-δ particles increase, their chemical composition becomes homogeneous, and the amount of cerium involved in oxidation and reduction increases. The composite containing 50 wt % Al2O3 is a mixture of Ce x Zr 1-x O2-δ and Al2O3 crystallites, whose size is practically unaffected by calcination. The (Pt/Al2O3 + Al2O3-Ce 0.75Zr0.25O2) based on this composite has the highest OSC and is the most active. For this reason, full-scale testing of this catalyst is recommended. © 2013 Pleiades Publishing, Ltd

Local study of lithiation and degradation paths in LiMn2O4 battery cathodes via scanning probe microscopy and confocal raman microscopy

The work was financially supported by Russian Science Foundation (Grant 17-72-10144). The equipment of Ural Center for Shared Use “Modern Nanotechnology” Ural Federal University was used

Quantitative characterization of the ionic mobility and concentration in Li-battery cathodes via low frequency electrochemical strain microscopy

The work was financially supported by Russian Science Foundation (Grant 17-72-10144). The equipment of the Ural Center for Shared Use “Modern nanotechnol-ogy” UrFU was used

Local study of lithiation and degradation paths in LiMn2O4 battery cathodes via confocal raman microscopy

The work was financially supported by Russian Science Foundation (Grant 17-72-10144). The equipment of Ural Center for Shared Use “Modern Nanotechnology” Ural Federal University was used

Local electronic transport across probe/ionic conductor interface in scanning probe microscopy

Charge carrier transport through the probe-sample junction can have substantial consequences for outcomes of electrical and electromechanical atomic-force-microscopy (AFM) measurements. For understanding physical processes under the probe, we carried out conductive-AFM (C-AFM) measurements of local current-voltage (I-V) curves as well as their derivatives on samples of a mixed ionic-electronic conductor Li1-xMn2O4 and developed an analytical framework for the data analysis. The implemented approach discriminates between contributions the highly resistive sample surface layer and the bulk with the account of ion redistribution in the field of the probe. It was found that, with increasing probe voltage, the conductance mechanism in the surface layer transforms from Pool-Frenkel to space-charge-limited current. The surface layer significantly alters the ion dynamics in the sample bulk under the probe, which leads, in particular, to a decrease of the effective electromechanical AFM signal associated with the ionic motion in the sample. The framework can be applied for the analysis of electronic transport mechanisms across the probe/sample interface as well as to uncover the role of the charge transport in the electric field distribution, mechanical, and other responses in AFM measurements of a broad spectrum of conducting materials. © 2020 Elsevier B.V.This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020 and UIDP/50011/2020, financed by national funds through the Portuguese Foundation for Science and Technology/MCTES. The work was financially supported by the Portuguese Foundation for Science and Technology (FCT) within the project PTDC/CTM-ENE/6341/2014. It is also funded by national funds (OE), through FCT ? Funda??o para a Ci?ncia e a Tecnologia, I.P. in the scope of the framework contract foreseen in the numbers 4, 5 and 6 of the article 23, of the Decree-Law 57/2016, of August 29, changed by Law 57/2017, of July 19. The authors thank Daniele Rosato (Robert Bosch, GmbH) for providing samples of Li-battery cathodes and useful discussions. Equipment of the Ural Center for Shared Use ?Modern nanotechnology? of the Ural Federal University was used in the experiments. The work has been supported in part by the Ministry of Science and Higher Education of the Russian Federation under the project #FEUZ-2020-0054

Electrochemical Strain Microscopy of Li-ion battery cathodes

The work was financially supported by the Portuguese Foundation for Science and Technology (FCT) within the project PTDC/CTM-ENE/6341/2014. The equipment of the Ural Center for Shared Use “Modern nanotechnology” UrFU was used